Background: The number of multiple pregnancies is considered to be the most important adverse effect of in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI). IVF or ICSI with transferring only one embryo, elective single embryo transfer (eSET), will reduce this incidence remarkably. Unfortunately, former research has documented that cycles with SET maintain lower pregnancy rates compared to double embryo transfer (DET). Implementation of eSET will require a carefully chosen and thoroughly defined implementation strategy focussed on the couple undergoing the subfertility treatment. This trial will investigate the (cost)effectiveness of a combined patient centred implementation strategy.